Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus.
Description of the Related Art
Recently users of electrophotographic apparatuses have been more diversified and higher image quality and higher stability are required in an output image more than ever before. Accordingly, the high image quality and high stability of an electrophotographic photosensitive member to be installed on electrophotographic apparatuses is required to be further improved.
As a technique for achieving excellent properties of an electrophotographic photosensitive member for a long period from the initial stage of image formation, in Japanese Patent Application Laid-Open No. 2002-55466, a technique for forming a charge transporting layer by drying a coat formed from a coating liquid which contains a charge transporting material, a binder resin, dimethoxymethane and an aromatic hydrocarbon solvent having a boiling point of 130° C. or higher is disclosed. Specifically, in Japanese Patent Application Laid-Open No. 2002-55466, a technique using anisole (methoxybenzene) as the aromatic hydrocarbon solvent is disclosed.
In Japanese Patent Application Laid-Open No. H07-261422, a charge transporting layer composition and an electrophotographic photosensitive member which contain an aromatic ether as solvent are described.
In Recent years, electrophotographic apparatuses have been installed in all over the world with the physical distribution to cover all over the world. Accordingly, electrophotographic apparatuses and electrophotographic photosensitive members are required to be improved in resistance to environment (low dependence on environment), such that the properties of electrophotographic photosensitive members are hardly changed by the difference in temperature and humidity between installation locations or by the change in temperature and humidity during physical distribution.
However, in the case of using methoxybenzene in manufacturing an electrophotographic photosensitive member as described in Japanese Patent Application Laid-Open No. 2002-55466, cracks were generated in the electrophotographic photosensitive member in some cases when stored in a high-temperature and high-humidity environment and then stored in a normal temperature environment, probably due to precipitation of the charge transporting material.
In the case of using an aromatic ether in manufacturing an electrophotographic photosensitive member as described in Japanese Patent Application Laid-Open No. H07-261422 also, the storage in the similar environment caused the similar cracks in some cases.
In both cases, the cause is presumed to be the presence of methoxybenzene (aromatic ether) in the charge transporting layer of the electrophotographic photosensitive member, for use in manufacturing the electrophotographic photosensitive member.